Electric convection heater and method of use for exterminating insects

ABSTRACT

An electric heater includes an upper housing, a lower housing, a fan disposed in the upper housing, and a heater disposed in the upper housing. Electrical control components and circuitry are disposed in the lower housing and are connected for energizing the heater and for operating the fan. Mechanical support members are arranged for spacing the upper housing from the lower housing in order to create air discharge flow paths for air flow exiting from the upper housing. The discharged air at an elevated temperature is used to elevate the temperature of objects within a room for exterminating bed bugs.

BACKGROUND OF THE INVENTION

The present disclosure is directed to the construction of an electric convection heater and the method of use of that heater for exterminating insects, specifically bed bugs. The use of heat for exterminating insects such as bed bugs is not considered new, but the types of heaters traditionally available have limited their use to larger structures with large open spaces, such as factories and warehouses. The present disclosure is directed to the construction and arrangement of an electric convection heater which is specifically designed for structures with smaller spaces or areas, such as residences and hotel rooms. For these smaller spaces or areas, size and weight of the heater is important in order to make the heater “portable”.

Convection heaters typically include a convection passageway in which a heating element is positioned. The ambient air to be heated is drawn into the passageway by convection and, as it flows across the heating element, the temperature of the ambient air increases. This causes an upward flow and the convection cycle, including the flow of air through the convection heater, continues. The use of “electric” to describe the disclosed convection heater is directed to the type or style of heating element which is used in the convection heater.

There are two primary forms or types of air-flow convection. The first is natural convection or free convection and the other is forced convection. Natural convection occurs due to temperature differences which affect the density and thus the relative buoyancy of the air. The less dense air rises, setting up a flow across the (electric) heating element in the case of an electric convection heater. Forced convection results from some type of external surface force, such as what would be produced by a fan or blower. Forced convection is typically used to increase the rate of heat exchange. However, several relevant factors are involved in the overall heat exchange event for an electric convection heater. Some of these relevant factors include the temperature of the ambient air, the surface area of the heating element, and the temperature of the heating element.

When the convection heater construction is based on natural convection and it is used for residential room heating, it is normal for the heater to be mounted or attached to a wall of the room. When the convection heater construction is based on forced convection, the heater can be recessed in a wall of the room. In either mounting configuration, the heating objective is to maintain the room temperature at a comfortable level for the occupants, perhaps a temperature in the range of 68 degrees F. to 74 degrees F. Further, in either mounting configuration the convection heater is stationary and its size and weight, in terms of transportability or portability, is not considered to be particularly important. However, if the convection heater is intended to moved from structure to structure, or from room to room within the same structure or even moved to various locations within the same room, then the size and weight of the convection heater become more important.

The electric convection heater according to the present disclosure is constructed and arranged for a specific application. This specific application is the driving force behind the specific mechanical and electrical features and operating parameters/specifications of the electric convection heater as disclosed herein. The specific application which is disclosed herein pertains to extermination of insects from within a room, specifically bed bugs. Certain insects, such as bed bugs, are able to be exterminated by subjecting them to an elevated temperature of at least 115 degrees F. for a sufficient period of time. The higher the sustained temperature, the shorter the period of time (i.e., duration) required for extermination.

An electric convection heater constructed and arranged according to the present disclosure is specifically designed to be used in a smaller confined space such as a room of a house or a hotel (or motel) room which is infested with bed bugs. However, the mechanical and electrical characteristics enable the disclosed electric convection heater to be used for exterminating other insects and can be used in other spaces or areas, including larger rooms. Notwithstanding this versatility, the focus herein is on exterminating bed bugs in terms of the requisite temperature and the time interval or duration for that desired temperature to be maintained.

In preparation for using the disclosed electric convection heater, the room with the infestation of bed bugs is closed and any obvious heat loss areas or locations are closed and/or covered. The idea is to try and achieve a rapid rise in the interior room temperature, focusing on the temperature of objects within the room such as bedding, carpeting, upholstered furniture and window coverings, and if significant heat loss occurs, the rise time to the desired interior temperature becomes longer. The disclosed electric convection heater is moved into the room and, depending on the room size, several electric convection heaters may be used. These individual electric convection heaters are small enough in size and light enough in weight to be considered “portable”. This enables each electric convection heater to be easily transported to and from the structure and easily repositioned within the room as well as easily moved from room to room within the same structure.

One objective is to get the interior of the room and importantly all of the furniture, carpeting, bedding, and fabric elements, such as window coverings, up to a minimum temperature of 115 degrees F. Ideally, the exterminating temperature is in the 130 degrees F. range so as to shorten the time duration. Once the desired temperature is achieved, it needs to be maintained for at least a few minutes so as to ensure near one hundred percent (100%) extermination of the infestation of bed bugs. Temperature sensors are used to monitor the temperature of the room and the objects within the room. These temperature sensors also monitor the uniformity of that temperature throughout the room and within those objects which might harbor bed bugs. A rapid temperature rise is important so as to kill the bed bugs before they are able to escape from the room.

When referring to the temperature to be maintained or the temperature of the room, it is the temperature of the bedding, carpeting, window coverings, and the furnishings of the room which is critical. These are the items which are likely infested with bed bugs and these are the items which need to be subjected to an elevated temperature which is sufficient to exterminate the bed bugs which may be found therein. Rather than merely checking the temperature of the air coming out of the heater or the ambient air temperature within open spaces of the room, the temperature of the bedding, carpeting, furnishings, window coverings, and related objects needs to be checked and maintained at an elevated level for a sufficient interval of time in order to exterminate the bed bugs.

BRIEF SUMMARY

An electric heater includes an upper housing, a lower housing, a fan disposed in the upper housing, and a heater disposed in the upper housing. Electrical control components and circuitry are disposed in the lower housing and are connected for energizing the heater and for operating the fan. Mechanical support members are arranged for spacing the upper housing from the lower housing in order to create air discharge flow paths for air flow exiting from the upper housing. The discharged air at an elevated temperature is used to elevate the temperature of objects within a room for exterminating bed bugs.

One object of the present disclosure is to describe an improved electric convection heater and method of use of that heater for exterminating insects, specifically bed bugs.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a front elevational view of an electric convection heater according to the present disclosure.

FIG. 2 is a front elevational view, in partial section, of the FIG. 1 electric convection heater, with the fan guard in exploded view form.

FIG. 3 is a side elevational view of the FIG. 1 electric convection heater.

FIG. 4 is a side elevational view of the FIG. 1 electric convection heater in fragmentary form showing internal components.

FIG. 5 is a diagrammatic illustration of selected electrical components for the FIG. 1 electric convection heater which are mounted on a support shelf internally.

FIG. 6 is a diagrammatic illustration of other electrical components associated with the FIG. 1 electric convection heater which are mounted on a separate support shelf internally.

FIG. 7 is a top plan view of a heater panel comprising one portion of the FIG. 1 electric convection heater.

FIG. 8 is a top plan view of the FIG. 1 electric convection heater showing the fan.

FIG. 9 is a top plan view of the FIG. 8 fan motor as mounted in position in an upper housing of the FIG. 1 electric convection heater.

FIG. 10 is an enlarged front elevational view of the FIG. 7 heater panel.

FIG. 11 is an enlarged left side elevational view of the FIG. 7 heater panel.

FIG. 12 is an enlarged right side elevational view of the FIG. 7 heater panel showing some of the wiring connections.

FIG. 13 is an electrical schematic corresponding to the electrical components and wiring of the FIG. 1 electric convection heater.

FIG. 14 is a partial electrical schematic of the heating and control circuit according to one disclosed embodiment.

FIG. 15 is another partial electrical schematic of the heating and control circuit according to one disclosed embodiment.

FIG. 16 is a schematic of the timing relay comprising one portion of the FIG. 13 schematic.

FIG. 17 is a schematic of the SCR relay comprising one portion of the FIG. 13 schematic.

FIG. 18 is a schematic of the temperature controller comprising one portion of the FIG. 13 schematic.

FIG. 19 is a schematic of the master switch comprising one portion of the FIG. 13 schematic.

FIG. 20 is a schematic of the ground connection comprising one portion of the FIG. 13 schematic.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated device and its use, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates.

Referring to FIG. 1-4, there is illustrated an electric convection heater 20 which is constructed and arranged for use within an enclosed space, such as a hotel room, in order to kill bed bugs. It is known that heat will kill bed bugs if a high enough temperature is maintained for a long enough period of time. There is a temperature-time relationship for killing bed bugs such that a higher temperature will reduce the required time interval. Importantly, the temperature which is relevant is the temperature of the environment which is infested with bed bugs, such as bedding, carpeting, upholstered furniture, fabric window coverings, and the like. Since bed bugs may be found in bedding, furniture, rugs, curtains, etc., it is the temperature of these items which is important, regardless of the air temperature within the room or the temperature of the air exiting from the electric convection heater.

With continued reference to FIGS. 1-4, convection heater 20 includes an upper housing 22, lower housing 24, heater panel 26, fan 28, and the remaining electrical components, connections, and controls, as illustrated and described herein. The electrical portions of heater 20 will be described in greater detail following the description and explanation of the main mechanical components.

The upper housing 22 is a rigid, sheet metal enclosure which is generally cylindrical and which receives and supports the fan 28 by a mechanical connection as well as receiving and supporting heater panel 26. The heater panel 26 (see FIG. 7) includes a uniform grid of individual heating elements 26 a which are arranged into the generally square panel as illustrated, and this panel occupies a majority of the cylindrical cross sectional area of upper housing 22. The heater panel 26 is securely attached to the inside surface 22 a of the upper housing 22 by four mounting brackets 30. One end 30 a of each mounting bracket 30 is welded to inside surface 22 a. The opposite end 30 b of each bracket 30 (inwardly positioned) is attached to heater panel 26 by the use of threaded fasteners. This construction technique allows the easy removal of heater panel 26 for repair, servicing, and/or replacement, if that becomes necessary, without disturbing the other components, except as required for access. The area 31 which is outlined in broken line form is intended to diagrammatically represent and depict an air deflector which is constructed and arranged to direct the air flow from fan 28 toward heater panel 26. Since air flow from a fan is proportionately higher (or a higher percentage) at the tips of the blades, using this air deflector helps redirect some of that air flow more towards the heater panel 26. The air deflector is riveted to the housing 22 side wall. An enlarged front elevational view of heater panel 26 is illustrated in FIG. 10. FIG. 11 illustrates the left side elevational view of heater panel 26, while FIG. 12 illustrates the right side elevational view of heater panel 26.

The fan 28 includes a fan motor 32 and a fan blade subassembly 34 securely assembled to the output shaft 36 of the fan motor 32. FIG. 8 shows a diagrammatic top plan view of the fan 28 as assembled into the upper housing 22. This drawing figure is described as being “diagrammatic” as certain component parts have been omitted simply for drawing clarity and to focus on the number, style, size, and location of the fan blades 38 of fan blade subassembly 34. As illustrated, there are six equally-spaced fan blades 38, each with a generally rectangular shape. The length of each fan blade is such so as to position the outer end 38 a of each fan blade in close proximity to the inner surface 22 a of the upper housing 22. The outer end 38 a of each fan blade 38 is curved slightly so as to generally match the curvature of inner surface 22 a. This design and the close proximity of outer ends 38 a to inner surface 22 a require that the fan motor 32 be securely connected to the upper housing 22 and that the motor output shaft 36 be substantially concentric with the generally cylindrical shape of upper housing 22. The mounting of the fan motor 32 to the inner surface 22 a is diagrammatically illustrated in the top plan view of FIG. 9. This drawing figure is also identified as “diagrammatic” since, as with FIG. 8, certain components have been omitted from the illustration simply for drawing clarity.

Referring to FIG. 9, fan motor 32 is securely attached to inner surface 22 a by the use of three mounting brackets 40 and three support arms 42. Each mounting bracket 40 is either bolted or welded to inner surface 22 a at one of three spaced-apart locations. These weld or bolt locations are generally equally spaced apart. One end 42 a of each support arm 42 is attached to a corresponding mounting bracket 40 by a threaded fastener. The opposite end 42 b of each support arm 42 is attached to a threaded mounting stud which is a part of the fan motor 32. As will be explained in greater detail herein, the electrical operation of fan 28 causes the mechanical rotation of the fan blade subassembly 34 and thereby a forced air flow across the grid of heating elements 26 a (which comprise heater panel 26) in a downward direction. A downward direction is defined herein as being a direction away from upper housing 22 and toward the lower housing 24. With the heating elements 26 a electrically energized and thus brought to an elevated temperature in a relatively rapid manner, the temperature of the forced air flow from fan 28 across heater panel 26 also becomes elevated prior to exiting from heater 20, at which point this heated air enters the room wherein heater 20 has been positioned.

With continued reference to FIGS. 1-4, lower housing 24 includes a deflector cone 44, a control panel 46, and two interior support shelves 48 and 50 (see FIGS. 5 and 6) which are constructed and arranged to receive various electrical components. These electrical components and their intended functioning within the overall electrical system will be described herein. The three equally-spaced, rigid support tubes 52 a, 52 b, and 52 c securely connect together the upper housing 22 and the lower housing 24 such that these two housing structures are generally concentric to one another and spaced-apart so as to define clearance spaces for heated air discharge. The air flow which is directed across heater panel 26 by fan 28 travels downwardly towards deflector cone 44, at which point the shape and geometry of the deflector cone 44 causes the heated air to deflect outwardly away from heater 20 with the discharge paths being from between the two housing sections 22 and 24, between the three support tubes 52 a, 52 b, and 52 c, and across the surface of the deflector cone 44. Deflector cone 44 may be formed as part of the overall sheet metal construction of lower housing 24 or may be a separate component attached to the lower housing 24 by threaded fasteners or welding. For added versatility in size and shape, and for ease in repair and replacement, deflector cone 44 is preferably a separate component.

The supporting structures for the connection and the stacked spacing of the upper housing 22 and the lower housing 24 are configured as hollow tubes and this allows for a simple and convenient routing of high temperature cable 54 from the electronics within the lower housing 24 to heater panel 26, as illustrated in FIG. 2. As for the electrical connection to the fan 28, the electrical cable 56 is routed through electrical conduit 58. Conduit 58, which extends from the lower housing 24 to above the upper housing 22 (generally in line with fan motor 32) is welded to the outer surface 22 b of upper housing 22. The welded construction of conduit 58 to surface 22 b and the wide range of material options for conduit 58, including variations in size and material strength, enable conduit 58 to be shaped with a handle portion (not illustrated) for lifting. A second handle portion component (not illustrated), which will be spaced apart from the first handle portion, can be added to the upper housing 22 as a second lifting point to help balance the first lifting point provided by the shaped portion of conduit 58.

Support tube 52 c which receives cable 54 also receives thermocouple cable 60 for the “safety” thermocouple 62. This thermocouple allows monitoring of the temperature within the upper housing 22. If that interior temperature reaches a set threshold, the heater panel 26 is shut down. The primary thermocouple 64 extends through deflector cone 44 in an upward direction and is positioned in one of the heated air discharge paths between the two housing sections.

Completing the description of the main or basic mechanical and electromechanical construction of upper housing 22, a fan guard 66 is used as an item of added safety. The fan guard 66 is attached to the upper edge of the upper housing 22 and is shaped so as to extend over and around the fan motor 32. The fan guard 66 protects users from the fan blades and prevents any foreign objects, which might be large enough to damage the fan blades, from falling or dropping into the upper housing 22. The fan 28 must still be able to pull a sufficient supply of air in from the surrounding atmosphere and thus the openings between the grill wires of fan guard 66 must be sufficient in size and number for the required air flow. While small objects might be able to pass through these grill openings, it is not expected that these objects would be of a size sufficient to cause any damage. The fan guard is effective to prevent ones hand or fingers from reaching the fan blades.

The preferred structural arrangement as illustrated in FIGS. 1-4 is to position the fan 28 above the heater panel 26 such that the fan pulls in atmospheric air and directs that atmospheric air across the individual heater elements 26 a in a downward flow path directed toward the deflector cone 44. An alternative construction option is to reverse the respective positions of the fan 28 and the heater panel 26. This would position the heater panel 26 near the top of the upper housing 22 and position the fan 28 below the heater panel 26 in a lower portion of the upper housing 22. In this alternative arrangement, the fan 28 pulls in air from the surrounding atmosphere and draws it across the heater elements 26 a.

The lower housing 24 encloses the two interior support shelves 48 and 50 and the electrical components mounted on each shelf are illustrated in diagrammatic form in FIGS. 5 and 6. In terms of the preferred mechanical construction, shelf 48 is positioned at the base of lower housing 24 and is attached to the inner surface 24 a of lower housing 24. Shelf 50 is positioned above shelf 48 and these two shelves can be attached to each other for added strength and rigidity. Shelf 50 is also attached to the inner surface 24 a of lower housing 24.

The control panel 68 of lower housing 24 includes a 480 volt 3-phase plug and receptacle 102, a master switch 146, a temperature controller 112, and three locking receptacles 124 a, 124 b, and 124 c. Shelf 48 is constructed and arranged with various electrical components mounted thereon and electrically connected (i.e., wired) as illustrated in the FIG. 13 electrical schematic and as applicable with regard to the other detailed schematic illustrations of FIGS. 14-23. Some of the electrical components which may be mounted onto shelf 48 include control power transformer 140, secondary fuse 142, 40 amp contactor 106, 480 volt 3 amp TD fuses 130, 3 amp 480 volt time delay fuses 122, 40 amp 480 volt fuses 104, overload relay 134, 480 volt 25 amp contactor 132, ground lug 120, timing relay 144, and 120 volt 1 amp fuse 142. Shelf 50, which also forms and provides control panel 68 by its sheet metal construction, additionally includes a 40 amp SCR power supply 108. Other electrical components are present as will be clear from the description of the electrical schematic beginning with FIG. 13 and with the detailed schematics of selected component parts and electrical arrangements as illustrated in FIGS. 14-23. The primary components which are mounted to shelves 48 and 50, including control panel 68, are what have been listed thus far. The specific component mounting locations are somewhat optional so long as all components of the FIG. 13 schematic are packaged in the heater in an efficient and safe manner

Referring now to the electrical schematic of FIG. 13 and the detailed electrical schematics of certain portions as illustrated in FIGS. 14-23, the primary embodiment of a heating and control circuit 100 is depicted in FIG. 13. The particular point-to-point connections between the various components are depicted in FIGS. 14-23. As shown, heating and control circuit 100 is powered by an external power source and connected to circuit 100 through receptacle 102. In one embodiment, receptacle 102 is a 480 volt three-phase receptacle. The power provided by the external power source is connected to a semi-conductor fuse set 104 and a contactor 106 before reaching power supply 108. In one embodiment, fuses 104 are 480 volt, 40 amp fuses having a clip connection. In one embodiment, contactor 106 has a 40 amp rating. The use of bolt-in fuses is one option.

Power supply 108 provides and controls current to heater panel 26. In one contemplated embodiment, power supply 108 is a silicon-controlled rectifier power supply. As but one example, power supply 108 may be a 40 amp DIN-A-MITE SCR power controller manufactured by Watlow having headquarters in St. Louis, Mo. Pursuant to one embodiment, heater panel 26 is a 20 kilowatt three-phase heating element.

Power supply 108 is also connected to temperature controller 112. In one contemplated embodiment, temperature controller 112 is an EZ-Zone temperature controller also produced by Watlow. Temperature controller 112 is communicatively connected to thermocouples 114 and 116. Thermocouple 114 is set to the operation temperature of heater panel 26. In one embodiment, the operational temperature is set to 140 degrees Fahrenheit. Thermocouple 116 is set to a safety shut-down temperature. In one embodiment, this safety shut-down temperature is 160 degrees Fahrenheit. Temperature controller 112 further includes a high temperature shut-down alarm 118. In one embodiment, shut-down alarm 118 activates contactor 106 when high temperature conditions exist which cause power supply 108 to cut off power to heater panel 26. In another embodiment, shut-down alarm 118 activates contactor 106 when a programmable operational temperature is reached.

As shown, power supply 108 is grounded to ground bus 120. Ground bus 120 provides a ground connection to all of the high voltage components shown herein. The specific ground connections for each component are depicted in FIGS. 14-23.

Receptacle 102 is also connected to a series of fuses 122. In one embodiment, fuses 122 are 3 amp, 480 volt time-delay fuses. Fuses 122 are electrically connected to a series of receptacles 124 a-124 c. Receptacles 124 a-124 c provide a locking receptacle for electrical connection with remote circulation fans 126 a-126 c (not illustrated in mechanical form or layout) via locking plugs 128 a-128 c. As discussed herein, remote circulation fans 126 a-126 c are external to the main heating and control circuit 100 and provide extra means to circulate the air heated by heater panel 26.

Fuses 130, contactor 132 and overload relay 134 are provided between external power resource receptacle 102 and main fan 28. Fan overload relay 134 is in communicative connection with temperature controller 112. Accordingly, the operation of main fan 28 is dictated, in part, from the temperature condition sensed by temperature controller 112. In one embodiment, fuses 130 are 480 volt, 3 amp time-delay fuses. In one embodiment, contactor 132 is a 480 volt, 25 amp contactor consisting of a 120 volt coil. Main fan 28 is a 480 volt fan having a 1 FLA rating.

Lastly, fuses 138 are provided before control power transformer 140. In one embodiment, fuses 138 are 480 volt, 1 amp fuses. Control power transformer 140 is a transformer providing a 480 volt to 120 volt step down. This step down is required to power the various components and controls at 120 volts.

Looking at the various components available downstream of the control power transformer 140, a fuse 142 is provided to protect the other downstream components from overvoltage conditions. In one embodiment, fuse 142 is a 120 volt, 1 amp secondary fuse. A timing relay 144 is also electrically connected to a variety of components within circuit 100. Among other things, timing relay 144 dictates that main fan 28 will operate for 30 seconds after heater panel 26 is shut off. This is performed via an electrical connection with contactor 132.

Also provided is a main switch 146 which includes two contact blocks 148 and 150. In one embodiment, contact blocks 148 and 150 are rated for 10 amps. As shown, timing relay 144 is activated by the contact closure from contact block 150. In one embodiment, it is the closure of contact block 150 which dictates that fan 28 will operate for 30 seconds after heater panel 26 is shut down.

The heating and control circuit 100 as depicted in FIG. 13 also provides a safety mechanism to shut down heater panel 26 in the event there is a failure with power supply 108. In the depicted embodiment, a current transformer (CT) 152 is provided on at least one phase lead line to heater panel 26. The CT 152 detects the current provided through the phase line. In one embodiment, a spiked current reading (for example, over 40 amps) by CT 152 indicates a problem with power supply 108 and causes contacts 154 to be closed.

FIG. 13 further depicts the electrical connection between temperature alarm 118, an interposing relay 156, a motor auxiliary contact 158 and contactor 106. This electrical connection ensures that contactor 106 cuts off power to power supply 108 and therefore to heater panel 26 if either of two conditions are detected: (1) high temperature alarm 118 signals an unsafe temperature condition is sensed by thermocouple 116, or (2) a power supply failure is detected by sensor 152. In either case, the auxiliary fan motor contact 158 is engaged for a period of time while no power is supplied to heater panel 26 in order to cool the heating elements within heater panel 26.

The method of using heater 20 for the extermination of bed bugs begins with identifying the room or space which has a presence of bed bugs sufficient to warrant an extermination effort. A first step is to move one or more heaters 20 into the room (or space) and establish a source of power for each heater 20, such as a stand-by generator. The next step is to assess the room, decide on the number of heaters 20 to be used, and the placement of those heaters to try and achieve a generally uniform or balanced elevated temperature throughout the room. The elevated temperature would preferably be generally uniform throughout, for more reliable exterminating results, and would be the sensed temperature in the objects which may have an infestation of bed bugs. Such objects would include bedding, carpeting, furniture, and fabrics, such as window coverings. A next step is to close off and/or seal up heat loss locations within the room such as doors and windows as well as any obvious cracks and openings in floors, walls, and ceilings.

Once the room is properly prepared, the next step is to strategically position a plurality of temperature sensors (probes) in the room as a way to monitor the uniformity of the elevated temperature throughout the room. While such temperature sensors may be used in the open areas of the room, bed bugs are typically found in bedding, carpeting, fabrics, furniture, and similar objects. As such, it is the temperature of these objects which is important for exterminating. Therefore, sensors should at a minimum be located in these objects to be sure that these objects are all heated up quickly to a sufficient temperature for a prompt exterminating of bed bugs. Separate air circulation fans can be used in the room to facilitate movement of the heated air from each heater 20 in order to achieve a more uniform elevated temperature throughout the room and importantly throughout the objects within the room that may harbor bed bugs. Once the room is prepared and the temperature sensors (probes) properly positioned, the heaters 20 are operated in order to elevate the temperature of the room objects to a level which will promptly exterminate any bed bugs. A part of the room preparation can include the placement of separate air circulation fans. Once the desired temperature is achieved and maintained for the requisite duration for extermination of the bed bugs, the room objects are inspected. Assuming that visual inspection confirms that the bed bugs have been exterminated, as would be assumed from the monitoring of temperature and time parameters sufficient for exterminating, the heaters 20 are shut down, at which point the room is restored to its original condition and the exterminating equipment is removed. Restoring the room to its original condition includes removal of any separate air circulation fans which may have been used. The portability of heaters 20 allows the easy transport of the heaters from room to room and from space to space, including movement from one structure to another. The compact size and portability of each heater 20 also enables the easy re-positioning of those heaters within a confined space if the temperature uniformity and balance is not what is desired.

One of the important features of the overall system and method is the 480 volt heater 20 and its internal construction and electrical characteristics which provide an ability to heat the enclosed space or room up to 140 degrees F. as soon as possible in order to keep bed bugs from escaping. While 115 degrees F., as previously noted, may be sufficient for extermination, assuming a long enough time interval at that temperature, there is a concern that, as the room gradually heats up, the bed bugs may sense some type of change in surroundings and may vacate the room through the floor and walls given their small size and the likelihood of cracks and openings. Since the time requirement for extermination is lowered as the temperature increases, elevating the temperature of the objects within the room up to 140 degree F. as soon as possible not only results in a much shorter time window for extermination, but a rapid temperature rise up to 140 degree F. should prevent at least a majority of the bed bugs from escaping. It is also important for the elevated temperature of the room and the objects within the room to heat up uniformly and to evenly distribute the heat to all portions of the room for heating all of the objects within the room which may harbor bed bugs. Although the free air in the room will likely heat up very quickly, extra time is required in order for saturating objects such as sofas, mattresses, carpeting, cabinets, window coverings, etc. with the desired elevated temperature due to their greater mass and content. The fan 28 produces 3500 CFM of 140 degree F. air. This equates to over 68000 BTUs of heat. The air temperature from the heater is set by the temperature controller to a target of 140 degrees F. Importantly, the output temperature of the exiting air cannot exceed that which will damage common household furnishings such as carpeting, wood floors, etc. As described, power is to be shut off to the heater panel by a thermocouple sensing temperatures over the target of 140 degrees F. Once the heater panel is shut off, the continued operation of the fan 28 and its 3500 CFM of air movement will lower the temperature very quickly. In fact, the heating up of the room and the cooling of the room are both very fast and, as the room heats up, the length of time the power to the individual heating elements stays on is shortened. This process of time on and time off happens very quickly so as to “soften” the load the heaters put on the stand-by generator which is required to run the system. The 140 degrees F. target output temperature will vary only slightly as the control reacts very fast. There are preferably at least three circulating fan outlets on each heater which are designed to make set up easier for the operator. The circulation fans aid the heater 20 in mixing the air in the space as fast and as evenly as possible.

While the preferred embodiment of the invention has been illustrated and described in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that all changes and modifications that come within the spirit of the invention are desired to be protected. 

1. An electric heater comprising: an upper housing; a lower housing; a fan disposed in said upper housing; a heater disposed in said upper housing; electrical control means disposed in said lower housing for energizing said heater and for energizing said fan; and mechanical means for spacing said upper housing from said lower housing in order to create an air discharge opening for air flow existing from said upper housing.
 2. The electric heater of claim 1 wherein said heater is disposed between said fan and said air discharge opening.
 3. The electric heater of claim 2 which further includes a conduit extending from said lower housing to said upper housing.
 4. The electric heater of claim 3 wherein said heater is constructed and arranged as a heater panel including a plurality of heating elements.
 5. The electric heater of claim 4 which further includes a deflector cone which is constructed and arranged as part of said lower housing.
 6. The electric heater of claim 5 which further includes a first thermocouple positioned in said air discharge opening.
 7. The electric heater of claim 6 which further includes a second thermocouple positioned in said upper housing.
 8. The electric heater of claim 1 which further includes a conduit extending from said lower housing to said upper housing.
 9. The electric heater of claim 1 wherein said heater is constructed and arranged as a heater panel including a plurality of heating elements.
 10. The electric heater of claim 1 which further includes a deflector cone which is constructed and arranged as part of said lower housing.
 11. The electric heater of claim 1 which further includes a first thermocouple positioned in said air discharge opening.
 12. The electric heater of claim 1 wherein said electrical control means includes a 480 volt, three-phase receptacle for connecting to an external power source.
 13. The electric heater of claim 12 wherein said electrical control means includes a SCR power supply.
 14. The electric heater of claim 13 wherein said heater is a 20 Kw, three-phase heater panel.
 15. The electric heater of claim 14 wherein said electrical control means further includes a temperature controller with a high temperature shut-down alarm.
 16. The electric heater of claim 15 wherein said electrical control means further includes a plurality of receptacles which are constructed and arranged for electrical connection to external components.
 17. The electric heater of claim 1 wherein said electrical control means further includes a temperature controller with a high temperature shut-down alarm.
 18. A method of exterminating insects from within a defined space by elevating the temperature within the defined space, said method comprising the following steps: (a) providing an electric heater; (b) identifying the defined space to be treated by exterminating insects; (c) providing a generator for supplying electricity to the electric heater; (d) providing temperature sensors to be used within said defined space; (e) placing said electric heater in said defined space; (f) connecting said generator to said electric heater; (g) positioning said temperature sensors at locations within said defined space; (h) energizing said electric heater to elevate the temperature of said defined space; and (i) operating said electric heater until the sensed temperature within said defined space exceeds 110° F.
 19. An exterminating system for insects which are found within a room of a structure, said exterminating system comprising: an electric heater; a generator electrically coupled to said electric heater; and a plurality of temperature sensors positioned within said room, said plurality of temperature sensors being constructed and arranged for monitoring an elevated temperature in said room due to operation of said electric heater.
 20. The exterminating system of claim 19 wherein said electric heater comprises: an upper housing; a lower housing; a fan disposed in said upper housing; a heater disposed in said upper housing; electrical control means disposed in said lower housing for energizing said heater and for energizing said fan; and mechanical means for spacing said upper housing from said lower housing in order to create an air discharge opening for air flow existing from said upper housing. 